1. Field of the Invention
The present invention relates to an apparatus for and a method of controlling the amount of current in a grip heater mounted in a tubular steering handle of a vehicle such as a two-wheeled cycle, a snow mobile, a personal watercraft, a three-wheeled buggy, or the like, or the tubular steering handle of an outboard motor or the like.
2. Description of the Related Art
Some vehicles such as two-wheeled cycles (motorcycles, bicycles, motor-assisted bicycles, etc.), snow mobiles, personal watercrafts, three-wheeled buggies, or the like have steering handles with left and right handle grips incorporating nichrome-wire or copper-foil heaters. There have been developed grip heater controlling apparatus for supplying a current from a power supply to those heaters to make the handle grips warm for allowing the driver to drive the vehicle comfortably in winter or cold climate.
Since the amount of heat generated by the heaters should preferably be adjustable depending on the atmospheric temperature and the driver, there has been proposed a grip heater controlling apparatus having a rotary potentiometer (or rheostat) for adjusting the amount of current supplied to the heaters (see, for example, Japanese Patent No. 3,231,247). The proposed grip heater controlling apparatus allows the driver to operate the potentiometer to adjust the amount of heat generated by the heaters as desired. If the potentiometer is positioned near either one of the grip heaters, then the driver finds it easy to operate the potentiometer.
Certain motorcycles or the like have handle covers which cover the handle grips as well as a brake lever and a clutch lever for the purpose of preventing air heated by the heaters from escaping as well as protecting the driver's hands from the wind.
However, if such a handle cover is provided on the handle, the handle cover covers the handle grip combined with the above potentiometer. Since the handle cover covers the potentiometer, the driver finds it difficult to operate potentiometer.
Furthermore, since the potentiometer is of the rotary type, it needs to be operated by two fingers, e.g., a thumb and an index finger, of the driver.